Written by: Tom Balderston and Kate Romero

Project Overview: Leota Development completed a new 3 Unit project in a walkable neighborhood next to Woodland Park Zoo in late 2023. The project replaced a single-family home with a detached home in front and two large townhomes on the improved alley. The project was designed by Akasha Architecture and built by Paul Williams. The 4-Star project includes the latest all-electric design and plenty of Built Green features.

The energy model for this project earned an ERI score of 54, which qualified this project for the performance pathway option on the Built Green checklist. The performance pathway allows more credit for items such as orientation and windows, the best-in-class heat pump electric clothes dryer, and the induction range; enabling the home to qualify.

Energy Use: The project is Built Green 4 star with 2 additional energy credits compared to the 2018 WA Energy Code minimums. It features advanced R-42 foam/FG Batt ceiling insulation, a high-efficiency Mitsubishi Ductless Heat Pump system, 100% LED lighting, efficient Heat Recovery Ventilation, and ENERGY STAR appliances.

Low Impact Development and Rainwater Catchment: The project features 100% pervious paving on parking and walks for stormwater infiltration, roof drains to biofilter planters, EPA Water Sense toilets, water-efficient fixtures and shower heads, and drought-tolerant and native landscaping with no lawns. The project has easy access to shops and transit, with a “Walkscore” of 80, and the front entry and shared parking encourage community.

Indoor Air Quality and Moisture Protection: The project features no carpets, Kraus "Natural Home" Engineered Oak Flooring that is EO certified for air quality, framing lumber moisture tested before drywall cover, low VOC interior paints, caulks, adhesives, and sealants, and cabinets and MDF trim that are CARB 2 certified for low added formaldehyde. The project also features a Wrap Shield high-performance exterior weather barrier with under-windowsill flashings, a drainage plane, and all bath and kitchen fans were tested for proper flow.

Materials with Reduced Environmental Impact: The project features cabinets, trim, tile backer, doors, and railings with recycled material content. Additionally, it has Kraus "Natural Home" flooring that is FSC certified, long-life Hardie Panel fiber cement exterior siding, a heat-welded TPO roof membrane, plastic decking with 55% recycled content, and exercised efficient framing practices with pre-cut studs and roof trusses. The project underwent 3rd Party Built Green Verification at the foundation, framing, and final stages.

Sitting on a stunning 5-acre lot nestled into the woods and surrounded by wildflowers and berries, the Samish Solar Home is a resilient oasis for a growing family of mountain bikers and nature enthusiasts.

This 4 bedroom, 3.5 bath, 2,345 square foot single family residence was built for a young family in Bellingham, Washington. The primary goal of this home was to serve as the owner’s permanent residence, even as their needs change over time, while adding a layer of resiliency towards our changing climate. The home was designed to support a growing family, temporary or permanent aging parents, a home office, and ample storage for outdoor recreation gear in the 1,936 square foot garage. Samish Solar home also features an additional sunroom on the south side of the house to enjoy the sunshine year-round.

The home is built using a post and beam structural system in addition to structural insulated panel (SIP) exterior walls and roof. The double-height, vaulted ceilings in the living room provide excellent daylighting for current use, but a floor system and internal walls could be added in the future to transform this 4-bedroom home into a 5- or 6-bedroom home.

Sustainable Envelope & Mechanical Details

Working in conjunction with the graphite infused SIP walls and roof (R-29 and R-59 respectively), triple pane Vinyltek windows, an R-20 insulated slab-on-grade foundation and R-23.6 ICF foundation walls help complete the envelope of Samish Solar Home. Due to the sandwich design of SIPs, the envelope of the project started out very airtight, however in order to push the tightness even further and achieve an ACH of 0.27, Aerobarrier aerosol sealant was used to complete the air sealing. This project also features the tried-and-true TC Legend Homes HVAC model combining a Chiltrix CX-34, Fantech Hero 250, and rooftop solar. The CX-34 heat pump unit provides both domestic hot water and space heating/cooling through a zoned radiant hydronic system on the first floor and a fan coil unit on the second. These superior insulated materials coupled with our HVAC system and tight envelope create this high efficiency and high-performance home.

Climate Change Resiliency

With significant south facing windows and shading eaves, this home takes advantage of passive solar heating and cooling, which will help regulate the home’s temperature as summer and winter temps become more extreme. The triple pane, argon-filled windows also help to create a better barrier to the extreme outdoor temperatures. Since the roof will take the brunt of the solar heat, Cool Roof certified metal sheeting was installed to further prevent the home from overheating in the summer by increasing the albedo. The Fantech Hero 250 HRV provides the home with a constant flow of fresh air filtered through its built in HEPA filtration. This home maintains healthy indoor air quality even at the height of wildfire season, providing a safe haven for its occupants, friends, and family. The biggest resiliency feature of this home is the 28,000 gallon rainwater catchment system that supplies water for the fire suppression system and domestic water. The rainwater is filtered through a sediment filter, activated carbon filter, and UV filter to ensure it is fit for domestic use. The catchment system, which was required due to site water availability limitations, was significantly upsized in order to add resiliency. With the understanding that significant periods of drought are likely in the future, the larger catchment system will ensure adequate domestic water for the home and provide self-sufficiency in the future. Low-flow and water sense labeled plumbing fixtures also help to reduce water demands. The homeowners also opted to upsize the rooftop solar array to a 10.8kw system with Enphase microinverters. The solar system is battery ready for future resiliency additions and provides the home with more power than it needs, making the project net positive and allowing the owners to power an electric vehicle in the future. There is also plenty of roof area where additional solar could be installed if energy needs of the home change in the future.

Accessibility

In designing this home, it was important to the client that we future proof for aging parents who may need to utilize mobility aids and to ensure they, themselves, can grow old in the home. This meant designing with the essential spaces, such as the laundry room and kitchen, located on the first floor. All of the doorways were also widened to 3’ and the first-floor shower was made curbless to help ensure this home is functional in all phases of the owners’ lives. The unheated breezeway between the house and garage provides a central, stepless entry point and protection from the elements. This space also serves as a shoe removal area with a built-in bench and coat storage. At both the main entry and side entry, a stepless large, covered patio was installed, which can serve as a fantastic gathering area for everyone without any limitations. Lastly, in a less conventional form of accessibility, Powerhouse Designs will be adding Samish Solar Home’s premade plans to their website so others can build this home with a lower upfront design cost.